. >>> tonight on "world news." war and peace. the president andgovernorromneyfaceoff about how to stop a nuclear iran. anthis just in, barbara walters on what president and mrs. obama just said to her about life after the white house. >>> a new hope for breast cancer. is this mysterious clue the answer for tens of thousands of women? >>> the kennedy tapes. tonight, hidden tape recordings of a fully human president, angry, probing, a little girl under his desk now all grown up telling you the biggest thing she learned about her father. and abc news exclusive. and family reunion, everyone who thought they were stealing the show at the emmys last night. are under from our tiny gladiator family today. she shows you what she's really like. >>> good evening. as we come on the air, president obama and republican presidential candidate mitt romney are in a duel over war and peace. 43 days before "your voice, your vote" the question is this, how does the united states stop iran from getting a nuclear weapon and taunting both of the candidates from the sidelines, the president of iran, m